Can any one give me a brief note about cancer
Answers
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body.[2][8] These contrast with benign tumors, which do not spread to other parts of the body.[8] Possible signs and symptoms include a lump, abnormal bleeding, prolonged cough, unexplained weight loss and a change in bowel movements.[1] While these symptoms may indicate cancer, they may have other causes.[1] Over 100 types of cancers affect humans.[8]
Tobacco use is the cause of about 22% of cancer deaths.[2] Another 10% are due to obesity, poor diet, lack of physical activity or excessive drinking of alcohol.[2][9][10] Other factors include certain infections, exposure to ionizing radiation and environmental pollutants.[3] In the developing world, 15% of cancers are due to infections such as Helicobacter pylori, hepatitis B, hepatitis C, human papillomavirus infection, Epstein–Barr virus and human immunodeficiency virus (HIV).[2] These factors act, at least partly, by changing the genes of a cell.[11] Typically, many genetic changes are required before cancer develops.[11] Approximately 5–10% of cancers are due to inherited genetic defects from a person's parents.[12] Cancer can be detected by certain signs and symptoms or screening tests.[2] It is then typically further investigated by medical imaging and confirmed by biopsy.[13]